As a fitness environment, gyms show the idea that anyone can get to their ideal weight and their ideal physique, whatever that ideal is. However, does the shredded look really mean you are fit and healthy? Well, that’s the big debate in the health and fitness community.
Fitness is considered where your body is, in terms of the physical work it is able to perform, where it is both healthy and strong. Being fit also takes into consideration things like fatigue resistance and energy allowance between leisure and high-stress situations. These are determined through a variety of tests looking at cardiorespiratory endurance, muscular strength, power and endurance, mobility, balance, speed, and body composition. It is this last component that is causing concern for health practitioners and general society.
Body composition looks at the amount of lean tissue like muscle, bone, and water is in the body and compares it to the amount of fat tissue based on the percent of total weight. The healthy ranges of body fat percentage are 16-29% for females and 6-19% for males. However, that doesn’t mean that everyone falls in this category; for example, someone can have a body fat percentage of 30, whether male or female and not have any health problems. These people are considered having obesity but metabolically healthy. Similarly, someone can be in the lower range of healthy body fat percentages and have metabolic health problems1. Yes, you can argue that the metabolically healthy person with obesity is more likely to develop metabolic problems due to the excess fat but they may not. They may live a perfectly healthy life and have no problems.
So what exactly do we know about this fit-fat paradox?
1. It’s not all about weight: Cardiorespiratory fitness (CRF) plays a big role in all-cause mortality risk. Research has suggested that cardiorespiratory fitness will outdo risks related to obesity2. Interestingly enough, this study also showed that those who were considered ‘fat’ but fit have lowered all-cause mortality risk than those who were normal weight but unfit.
2. The role of genetics and physical activity: genetics and environment can play an influential role in adiposity and level of CRF. Genetics can play up to a 50% role in these markers but that means that environmental factors contribute to the rest of the influence3.
3. May also apply to children: It used to be thought that the fit-fat paradox did not apply to children, however, we are now seeing that this may not be the case. Right now, the data is inconsistent but is leaning towards a similar effect seen as in adults. Children with lower levels of obesity, those between the 85th and 95th percentiles, have lower mortality risks than their unfit and normal weight counterparts. After the 95th percentile, the data is very inconsistent4.
Even though we know this information, there is still information that we don’t know, but researchers are getting closer and closer to the answers. Here at York University, Professor Jennifer Kuk of the Faculty of Health has done studies on this very topic. Her research has shown that those with severe obesity, or people who have a BMI greater than 40, can see great health changes with 2.5 hours of exercise a week without aiming for weight loss. See the video through the link below to see the summary of her study.
Resources:
Kramer CK, Zinman B, Retnakaran R. Are metabolically healthy overweight and obesity benign conditions? A systematic review and meta analysis. 2013. In: Database of Abstracts of Reviews of Effects (DARE): Quality-assessed Reviews [Internet]. York (UK): Centre for Reviews and Dissemination (UK); 1995-.Available from: https://www.ncbi.nlm.nih.gov/books/NBK174043/Ortega FB, Lavie CJ, Blair SN. Obesity and Cardiovascular Disease. Circ Res 2016;118:1752–70.doi:10.1161/CIRCRESAHA.115.306883 Ross R , Blair SN , Arena R , et al. Importance of assessing cardiorespiratory fitness in clinical practice: A case for fitness as a clinical vital sign: A scientific statement from the American Heart Association. Circulation 2016;134:e653-e699.doi:10.1161/CIR.0000000000000461 Nyström CD, et al. Diabetes Care. 2017;doi:10.2337/dc17-1334.